The subject invention relates generally to a method and apparatus for lifting and stabilizing of subsided slabs, flatwork and foundations of buildings. The subject invention also pertains to a bracket and a slap pier assembly which can be used in the repair and support of subsided slabs, flatwork, and/or foundations.
Structural damage to a home or building can occur when the foundation or flatwork has settled or shifted out of position. This settling or shifting of foundation or flatwork can be caused by, for example, shifting or weaknesses in unstable ground. Typically, repair of a subsided slab involves inserting pier column, such as a pipe or pole, into the ground until reaching a load bearing strata, e.g, stable bedrock, coupling a slab support structure to the pipe or pole, and lifting the subsided slab with the slab support structure. To begin, a hole is often drilled through the foundation or slab in order to insert the pipe and the slab support structure used in lifting and restoring the foundation. Various size holes can be drilled depending on the specific method and apparatus employed. The slab can be lifted by the slab support structure as the slab support structure is raised with respect to the pipe or pole, and the weight of the slab can then be supported by the pipe or pole via the slab support structure. These excavation sites can be refilled at the end of the procedure with, for example, grout. Insertion of the pipes and the lifting of the slab support structures can involve complicated hydraulic pumps and lifts, with many nuts and bolts.
Some prior methods utilize a plate as a slab support structure. Relying on a plate can create a point, or a limited area, of contact support. This can cause undo stress on the area of the slab in contact with the plate which can potentially damage the slab.
Accordingly, there is a need for a method and apparatus for creating a larger area of contact between a slab support structure and a slab, flatwork, and/or foundation.
The subject invention pertains to a method and apparatus for lifting and stabilizing subsided slabs, flatwork, and/or foundations of buildings or other structures. The subject invention also relates to a bracket and a slab pier apparatus which can be used in the repair and support of subsided slabs. A specific embodiment of the subject method involves a bracket having one or more angles and corresponding brace pieces which form triangular sections, which can attach to a pier column, such as a pipe or pole, and provide a three dimensional structure for supporting a slab. The pier column can have a variety of cross-sectional shapes, such as square, circular or oval. The bracket is not limited to a triangular shape. Other shapes for the subject bracket can also be implemented, e.g., a rectangle, square, or curved shape, can also be utilized. A separate top piece can rest on the pier column and provide support to raise the bracket. In a specific embodiment, this top piece can provide support to raise the bracket by the use of one or more threaded rod and nut assemblies. The subject invention can utilize optional rebar or other appropriate material connected to the bracket, in situations where greater support of the subsided slab is needed. The subject invention provides a method for supporting a subsided slab using a small number of components and straightforward procedure.
The subject method and apparatus can be used to support the subsided slab over a large surface area. In a specific embodiment, concrete, grout, or other supporting material can be used to fill the excavated area so as to create a plug on which the slab can rest. The plug can envelop a portion, if not all, of the subject bracket. By enveloping the bracket, and or any other reinforcement structure attached to the bracket, the resulting plug, or reinforced pile cap can have increased tensile strength as compared with concrete, grout, or other supporting material without such reinforcing bracket or other reinforcing structure. Such a reinforced plug can act to distribute the force applied to support the slab to a broader area of the slab. Accordingly, the bracket, and any other structure attached to the bracket can provide strength to the plug. Rebar attached to the bracket can also provide additional strength to the plug.